1. Field of the Invention
The present invention relates to an alternating-current dynamoelectric machine having a rotor in which permanent magnets are disposed between adjacent claw-shaped magnetic poles.
2. Description of the Related Art
Conventionally, automotive alternators are known in which permanent magnets are disposed between adjacent claw-shaped magnetic poles to reduce magnetic flux leakage between the adjacent claw-shaped magnetic poles. (See Patent Literature 1, for example.)
Patent Literature 1 Japanese Patent No. 2548882 (Gazette: FIG. 3)
In such constructions, one problem is that when the claw-shaped magnetic poles are viewed in a direction of rotation of the rotor, the permanent magnets protrude from a plane of projection formed by adjacent claw-shaped magnetic poles overlapping, and since protruding portions do not contribute to reductions in magnetic flux leakage, excessive volume is required in the permanent magnets to improve their properties, increasing costs proportionately.
Another problem is that increasing the volume of the permanent magnets also proportionately increases centrifugal force acting on the rotor, making durability poor.